Ureas



UnitedStates Pateil o 7 1 I W FredApplegath and Raymond A. Franz, 'El Dorado, Ar ln,

assignors to Monsanto Chemical Company, St. Louis,.

Mo.,:a corporation of Delaware No Drawing. Application March 18, 1957 Serial No. 646,582

8 Claims. 01. 260-'- 77.5)

This invention relates to ureas and more particularly an object of this invention to provide an entirely new process for preparing cyclic and polymeric ureas. A particular object of this invention is to provide aprocess for preparing cyclic and polymeric ureas from carbon monoxide, sulfur and organic diamines. Other objects to the preparation of polymeric and cyclic ureas It is:

2,874,149 Patented Feb. 17, 1959 2 mately 22.4 g. of dihydroimidazolone were obtained, havin'g'a' melting point of 128-90 C., representing a 58% yield. Dihydroimidazolone is represented by the following formula:

HIOV GHQ HN NH EXAMPLE II The procedure set forth in Example I was repeated usingfl2'0 g. of 1,2-propylenediamine, 8.65 g. sulfur, 200 ml. of methanol and "an amount of CO suflicient to pressure thebOinb to 75 p, s. i. g. A 77% yield of 4-methyldihy'drjo-Z-iin'idazolone, having a melting point of. 119- 121 C., was obtained. 4-methyldihydro-2-imidazolone will become apparent from the description of this invention.

It has now been discovered that cyclic and polymeric ureas can be prepared by reacting at an elevated temperature carbon monoxide, sulfur and an organic compound selected from the group consisting of organic compoundscontaining at least two NH substituentz radicals and organic compounds containing'at least two -NH gsubstituent radicals and at least one..--NH--.

substituent radical. Such compoundsare hereinafter referred to as organic .diarnines. The positionof the amino.

groupswith respect to each other in the 'organicidiamine determines theytype of ureagformed in accordance with; this invention. In the case of aromatic organic .diamines,

cyclic ureas (imidazoles) are formed when the v.substituent radicals referred to aboveare attached to adjacent aromatic carbon atoms, that is, are in the ortho "position with respect to each other; and polymeric ureas are formed when the substituent radicals referred to above are attached to aromatic carbon atoms which arenot adjacent to each other; tor example, areg in the meta :or para :posi" tion with respectto each other. In the casevofralliphatica organic diamines, -cyclic ureas. (imidazoles) are formed: when the substituent radicals referred to;abo ve-areat-* tached to separate carbon atoms ;inthe same chainqwhich carbon atoms are linearly separated from each other by not more than three atoms and polymeric-=ureas ,;.are formed when the substituent radicals referred to above are attached to separate carbon atoms in the same achain and which carbon atomsare linearly separated from each other by more than three atoms. The following examples illustrate the invention EXAM L 1 Thirty grams of ethylenediamine, 16, g. 0f sulfur and. 3.00 ml. of methanol wereficharged to 1.81". stainless steel oxygen bomb. Carbon monoxide was introduced. into the? bomb vuntil a\pressure'of 130 p. s. i. g. was-obtained:-

The bomb was closed and heated, y-maintainin'g a-tempera ture of apiproximately"100: C. for "two hours; Theybonib was then allowed to-cool; the'll S' vented from the .bomb' and the contents removed by rinsing with methanol. The mixture was cooled and precipitated sulfur removed by filtration. The filtrate was evaporated to a volume of about 75-100 ml., cooled thereby precipitating dihydroimidazolone which was removed .by filtration. Approxiis represented by the following formula:

H(IJCH2 HN NH W EXAMPLE 111' The procedure set, forth in Example I was repeated using 20 g. of 1,3-fdiamino-2-propanol, 7.12 g. of sulfur,

200 m1. of methanol and an amount of O0 to pressure the bomb to '95 p. s. i. g. In this case the reaction was arorj zo. minutes at 121 c. A 65% jyield"(-l 6.8 g.,) of 5-hydroiry 2 tetrahydropyrimidone, having amelting.

point of 208 -210 C., was' obtained. S-hydrOxy-Z-tetrahydropyrimidoneisrepresented by the following formula:

, "E M LE Iv I The proc'edure st forth in Eiraniple V was repeated using a'two gallon stainless steel autoclave; 396 'g.' of 1.4-

; diaminobutane, 144 g. of sulfur, 38001111. of methanol and an amount of CO to pressure the autoclave to 375 PxS. i. g. Thereactionwas carried out for 2 hours at 100 6.- -A'54.6%' yield- (280 g.) of tetramethyleneurea, havinga melting poin't of 165-166 C., was obtained.

Tetramethyleneurea is represented by the following i using 10;g..pf pentamethylenediaminc 3.14; g. of; sulfur,

:- gpentamethyleneurea -having a melting point of 263- riil.-of methanol and an amount of O0; to pressure the autoclave to 1-QQ p. s.i g. Thereactionavas carried out at 1;2 0?- C.-for .2 hours. An-89.4%. yield (11.15-g.) .of

3 265 C., was obtained. The pentamethyleneurea thus obtained had the following chemical analysis:

Carbon Hydrogen Nitrogen Percent Percent Percent Calculated for: CeHuNzO 56. 22 9.44 21. 86 Actual 5 56.44 9.53 21.96

Pentamethyleneurea is represented by the following formula: I a

EXAMPLE VI ing formula:

C=O H EXAMPLE VII EXAMPLE-VIII The procedure set forth in Example I was repeated using 25 g. of diethylenetriamine, 11.7 g. of sulfur, 200 ml. of methanol and an amount of CO to pressure the bomb to 110 p. s. i. g. The reaction was carried out for 20 min. at 120 C. 1,3-bis(2-imidazolidonyl-2ethyl urea was obtained having a melting point of 1651 67 C. and the following chemical analysis:

Carbon Hydrogen .Nitrogen i 1 Percent Perc mt Percent Calculated I01! cuHzoNsoa 46. 47 7. 09 29. 55 .Actlial 1,3-bis(2-imidazolidonyl 2-ethyl)urea is represented by the following formula:

HzC-CH2 7 EXAMPLE IX 7 To a 2.1 stainless steel autoclavewas' charged 108 g.of m-phenylenediamine, 10.9"-g.of tr'ie'thylamine', '64 g. of sulfur and an amount of CO to pressure the autoclave to 450 p. s. i. g. With stirring, the autoclave wa s-heated to 120 C. for four hours. The contents were then removed 1,1'-ethylene-bis-Z-imidaZolone is' and unreacted amine extracted with hot methanol.

An 18% yield of poly-m-phenyleneurea having a melting point above 300 C. was obtained. The repeating unit of the polymer is represented by the formula:

EXAMPLE X To a 1.8 1. stainless steel bomb was charged 13.8 g. of 2,4,6-triaminotoluene, 9.7 g. of sulfur, 450 ml. of methanol and an amount of CO to pressure the bomb to 100 p. s. i. g. Thereaction was carried out at 115 C. for 3 /2 hours. The contents of the bomb were evaporated to about 200 ml. to precipitate the polymer. A 26% yield of a cross-linked polymer having a melting point of 310 C. was obtained.

EXAMPLE XI To a 1 l. autoclave was charged 30 g. of 2,4-diaminophenol hydrochloride, 9.76 g. of sulfur, 54.2 g. of tria above 300 C. The repeating unit of this polymer is represented by the formula:

use

ethylamine and CO to a pressure of 100 p. s. i. g. The autoclave was heated to 115 C. for 3 /2 hours. The polymer was washed with benzene, water and dilute HCl and a 72% yield (24.5 g.) of poly-m-(4hydroxyphenylene)urea recovered. The repeating unit of this polymer is represented as follows:

EXAMPLE XII To a 1 l. autoclave was charged 28.2 g. of benzidine, 9.76 g. of sulfur, 54.2 g. of triethylamine and CO-to a pressure of 100 p. s. i. g. The mixture was maintained at 115 C. for 3 /2 hours. The product was washed with dilute HCl and a Na S NaOH solution and a'46% yield 14.6 g.) of poly-p,p-biphenylenurea obtained melting o Y i 11 H n 00 I j EXAMPLE XIII The procedure of Example XII was repeated using 32.4 g. of 'o-tolidine, 9.76 g. of sulfur, 54.2 g. of triethylamine and CO to a pressure of-IOO p. s. i. g. The reaction was carried out at 115 C. for 3% hours. A 54% yield (14.5 g.) of poly-4,4-(3,3-dimethylbiphenylene)urea having a melting point'above '300" C. was obtained. The repeating unit of this polymer is repre sented by the formula:

H H H EXAMPLE XIV The procedure of Example )GI was repeated using 3.0 g.:o 2,4-diaminotoluene, 24g. of sulfur, 2.5 g. of

[Gail EXAMPLE XV H The procedure set forth in Example XII is repeated using'25 g. of o-dianis'idine, 9.8 g. of sulfur, 54.2 g. of triethylamine and CO to a ressure of 250 p. s. i. g.

reaction is meant groups which do not prevent the formation of any of the desired urea. Such substituent groups include alkyl, aryl, cycloalkyl, alkenyl, carboxy, hydroxy, thiol, cyano, halogen, including Chlorine, bro- The reaction was run for 3 hours at 115 C. A 11% 5 fluorine and i i l organosily yield (3.0 g.) of poly-4,4-(3,3'-dimethoxybiphenylene)- 9 l f k q, -Orgamc urea was obtainedhavinga decomposition point of 230 i cqntammg 8 {note If: q i be The repeating unit of this polymer is represented used. Size of the organic diamine in this regard is not by the formula: 10 l t.

Although not essential, it is desirable in most cases (Joni 0 to carry out 'the process in the presence of an inert g 60% lg a solvent or diluent. Aliphatic alcohols, particularly methanol, are preferred for this purpose as they are easy to separate and recover from the urea product, e. g.'

EXAMPLE XVI by evaporation, and they are solvents for many of the The same general procedure of Example XII was'reamines. Aromatic'and aliphatic hydrocarbons, chloripeated using the 2 l. Parr'bomb and 88 g. of bis-3- nated hydrocarbons, ethers, tertiary amines and acid (aminopropyl) ether, 21.2 g. of sulfur, 400 ml. of methaamides are also suitable. Water' per se is not a satis- 1101 and CO to a pressure of 700 p. s. i. g. The reaction a factory diluent although small amounts of water in the was ,carried out at 120 C. for'4 hours. A 100% yield organic diluent can be tolerated. Where a diluent is (105 g.) of poly-(ditrimethyleneoxy)urea was obtained employed, an amount suificient to slurry the reactants having a melting point of 1'91-193 C. As determined is usually sufficient. It is also preferred, but not necesfrom the specific viscosity of a 1.0 g. sample of the poly sary, to have a diluent in which the reactants are soluble. mer in 100 ml. of 95% H 80 at C., the polymer 25 In preparing ureas of the class described, the use of exhad a degree of polymerization of 20. The repeating cessively large amounts of solvent should be avoided. unit of this polymer is represented by the formula: Although not intended to be limitative, in addition to O methanol, the following solvents or diluents can be em- H i H ployed in carrying out the process: ligroin, isopropanol, N- CH2OI,H2CHQOCH2OH2OH2 N & isopropyl ether, ethanol, mineral oil, triethylamine, pyr- EXAMPLE XVII 3O idine, isopropanol-water, ethylene glycol, methyl Cello To a two gallon autoclave was added 4 of solve, tetrahydrofurfuryl alcohol, N,N-dimethylaniline, phenylenediamine, 432 g. of sulfur, 271 g. of triethyla- N,N-d1ethylethanolam1ne, formannde, amyl alcohol, and mine, 900 ml. of pyridine and CO to a pressure of 500 benzenep. s. i. g. The reaction was carried out for 2 hours 35, genfiral P ofthls mvemm reqmfes at 1180' c; The reaction product was then washed twice no added catalyst. The reaction proceeds in an alkal ne with CS once with a concentrated Na s solution and medlllm and {most cases the ammes s v Provld? then refluxed with a concentrated Na s solution. The fi In die-case of the use of Polymer was then washed twice with Water and dried organic dlamines, an alkaline catalyst, although not abso- A 100% yield (600 of po1y p pheny1eneurea was 40 lutely required, has been employed to advantage. Alkaobtained having a degree of polymeri ti of 14 and line catalysts having dlSSOClfltlOIl constants greater than a molecular weight of .1876. The repeating unit of this 353 g pggi g f i' g; 3 5 fi gg g gg g g i Polymer 18 represented by formula catalyst is desirable, it is not absolutely necessary. In H H the absence of added alkaline catalysts of the type disc cussed herein, the reaction still proceeds but with lower yields.

EXAMPLE XVIII Strong and weak inorganic bases appear to initiate the reaction about equally as Well, although the result- The followmg polyureas were Prepared a 100 ing yields of the urea are inferior to the preferred tertiary 9 In each case there was employed 0'017 mole of amine. Inorganic hydroxides, alkaline inorganic and 2: 8 :2 :r-2s sz1r?: 5%% s g 2233??? organic salts and tertiary aliphatic amines are useful as catalysts. Tertiary alkylamines are preferred. Qated the followmg Table Degree r j f The amount of catalyst to be added to assist in initiattlOll was determined from the P C VlScOsltY ing the reaction will vary depending upon the compound of gof the P y in 1111 of 95% 2 4 at 55 selected. From about 0.002 to about 0.2 mole of the 25 C. alkaline catalyst per mole of aromatic diamine is par- Table 1 Reaction Reaction Yield Softening Diamine reactant temp., time, Polymer produced percent DPn point,

0. hrs. 0.

Hexamethylenediamiue t 4 Polyhexamethyleneurea..- 73 22 D 2 do 59 30 D0 1 do 49 s Octaruethyleuediamine 160 l Polyoctamethyleneurea.-- 71 12 240-255 Decamethylenediamine 160 1 Polydecamethyleneurea. 80 7 240 Dodeeamethylenediamine 160 1 Polydodecamethyleneurea. 83 6 200-210 In addition to the organic diamines used in the preceding examples, organic diamines substituted with one or more substituents, in addition to those already illustrated, and which are not deleteriously reactive under the conditions of the reaction, can be used in'the reaction of this invention. By the expression groups which are not deleteriously reactive under the conditions of the ticularly useful although significantly greater quantities of catalyst, as shown by the examples can be used if desired.

The quantities of reactants used in this process can be varied substantially without departing from the scope of the invention. In general at least stoichiometric proportions of reactants should be used. Excessive quantities ofany of the reactants can be used as desired. The process has been found to be particularly operable using molar ratios of organic diamine to sulfur ranging from 0.121 to 8:1. Even higher ratios have been used with good results. Generally the particular ratio of reactants will be dictated more by economic considerations than by reactivity considerations.

The quantity of carbon monoxide used in the process can be varied substantially with it being employed in excess of the 'stoichiometric proportion and the excess being governed primarily by the pressure desired.

The process of this invention is operable over an exceptionally wide pressure range. It can. be operated at atmospheric pressure although the reaction proceeds much more rapidly at elevated pressures. Generally pressure from about 30 p. s. i. a. (pounds per square inch absolute) to about 1500 p.s. i. a. are applicable. Higher pressures can be used, if desired, but offer no advantage.

The process of this invention can be carried out over a wide temperature range. It is preferably carried out at an elevated temperature. Temperatures ranging from about 60 to about 300 C. have been found applicable. Generally, reaction temperatures in the range from about 60 C. to about 160 C. are preferred being varied slightly depending upon the urea produced. This application is a continuation-in-part of co-pending application Serial No. 593,040, filed June 22, 1956, now abandoned.

What is claimed is:

1. A process for preparing cyclic and polymeric ureas which comprises mixing carbon monoxide, sulfur and a compound selected from the group consisting of organic compounds containing at least two -NH substituent radicals attached to different carbon atoms and organic compounds containing at least one --NH substituent radical and at least one NH- substituent radical attached to different carbon atoms and subjecting the resultant mixture to a temperature in the range of from about 60 C. to about 300 C. and a pressure of at least 30 p. s. i. a. for a time suflicient to produce the urea.

2. A process as described in claim 1 wherein the resultant mixture is subjected to a temperature in the range from about 60 C. to about 160 at least 30 p. s. i. a.

C. and a pressure of.

ide, sulfur and 1,4-diaminobutane and subjecting the re sultant mixture to a temperature in the range from about C. to about C. and a pressure of at least 30 p. s. i. a. for a time sufficient to produce tetramethyleneurea.

5. A process which comprises mixing carbon monoxide, sulfur and o-phenylenediarnine and subjecting the resultant mixture to a temperature in the range from about 60 C. to about 160 C. and a pressure of at least 30 p. s. i. a. for a time sufficient to produce benzimidazolone.

6. A process which comprises mixing carbon monoxide, sulfur and p-phenylenediamine and subjecting the resultant mixture to a temperature in the range from about 60 C. to about 160 C. and a pressure of at least 30 p. s. i. a. for a time sufficient toproduce polyphenyleneurea.

7. A process which comprises mixing carbon monoxide, sulfur and bis-3-(aminopropyl) ether and subjecting the resultant mixture to a temperature in the range from about 60 C. to about 160 C. and a pressure of at least 30 p. s. i. a..for a time sufficient to produce poly- (di-trimethyleneoxy)urea.

8. A process which comprises mixing carbon monoxide, sulfur and hexamethylenediamine and subjecting the resultant mixture to a temperature in the range from about 60 C. to about 160 C. and a pressure of at least 30 p. s. i. a. for a timesufiicient to produce polyhexamethyleneurea.

References Cited in the file of this patent UNITED STATES PATENTS 2,615,025 Lutz Oct. 21, 1956 2,820,024 Kerk Jan. 14, 1958 FOREIGN PATENTS 679,671 Great Britain Sept. 24, 1952 OTHER REFERENCES Hagelock: Chem. Abstracts, vol. 44, cols. 9937-8. Uno et al.: Chem. Abstracts, vol. 47, col. 386. 

1. A PROCESS FOR PREPARING CYCLIC AND POLYMERIC UREAS WHICH COMPRISES MIXTURE CARBON MONOXIDE, SULFUR AND A COMPOUND SELECTED FROM THE GROUP CONSISTING OF ORGANIC COMPOUNDS CONTAINING AT LEAST TWO -NH2 SUBSTITUENT RADICALS ATTACHED TO DIFFERENT CARBON ATOMS AND ORGANIC COMPOUNDS CONTAINING AT LEAST ONE -NH2 SUBSTITUENT RADICAL AND AT LEAST ONE -NH- SUBSTITUENT RADICAL ATTACHED TO DIFFERENT CARBON ATOMS AND SUBJECTING THE RESULTANT MIXTURE TO A TEMPERATURE IN THE RANGE OF FROM ABOUT 60* C. TO ABOUT 300* C. AND A PRESSURE OF AT LEAST 30 P. S. I. A. FOR A TIME SUFFICIENT TO PRODUCE THE UREA 